CHAPTER-1 INTRODUCTION3 1.1 Fabrication The polymer material are converted into plastics and used as tubes, sheets, foams, rods, adhesives, etc., The theological properties, softening, tempering, stability, the size and shape are important in describing the method. These methods are different kinds of plastics. Broadly speaking the method may be discussed under the following headings, a. Moulding Process b. Foaming Process 1.1.1. Moulding process: In this process the plastics are fabricated under the effect pressure and heat and both thermoplastics and thermosetting plastics may be starting materials. Thermoplastics are produced by this method. In this the material is softened by heating and the hot softened plastic is forced under high pressure into the mold, when it is set by cooling and the mold is. 1.1.2 Foaming process: This involves the blowing of a volatile organic liquid, which is entrapped into a polymer network resulting in the formation of foamed plastics. polystyrene are produced in this process. Foamed 1 CHAPTER-2 2.1 Components The main components of the pneumatic injection moulding machine are, • • • • • • • • • Pneumatic Double acting Cylinder Hooper Barrel Heating Coil and regulator Direction control Valve Flow control valve L-Angle Nozzle • Die and Hose connectors a. Pneumatic Double Acting Cylinders: A double acting cylinder is employed in control systems with the full pneumatic cushioning and it is essential when the cylinder itself is required to retard heavy messes. This can only be done at the end positions of the piston stock. In all intermediate position a separate externally mounted cushioning derive most be provided with the damping feature. The normal escape of air is out off by a cushioning piston before the end of the stock is required. As a result the sit in the cushioning chamber is again 2 compressed since it cannot escape but slowly according to the setting made on reverses. The air freely enters the cylinder and the piston stokes in the other direction at full force and velocity. b. Hooper: The hopper is used to pour the plastic raw materials in to the barrel. c. Barrel: The barrel is used to hold the molten and unmated plastic raw materials. d. Heater and Regulator The heating coil is used to melt the plastic raw materials to the molten Form which is inside the barrel The heating coil regulator is used to regulate the temperature of heating coils according to the type of plastic raw materials used. e. Direction Control Valve: To control the to and fro motion of cylinder, the fluid energy has to be regulated, controlled and reversed with a predetermined sequence in a pneumatic system. Similarly one may have to control the quantity of pressure and flow rateto generate the desired level of force and speed of actuators. To achieve these functions, valves are used. Valves are fluid power elements used for controlling and regulating the working medium. The main functions of the valves are, • Start and stop the fluid energy • Control the direction of flow of compressed air • Control the flow rate of the fluid • Control the pressure rating of the fluid 3 f. Flow Control Valve: These are used to control the rate of flow of a fluid through the valve. A directional control valve on the receipt of some, external signal, which might be mechanical, electrical or a fluid pilot signal, changes the direction of stops, or starts the flow of fluid in some part of the pneumatic/hydraulic circuit. They can be used to carry out such functions as: 1. Controlling the direction of motion of an actuator 2. Selecting alternative flow paths for a fluid. 3. Stopping and starting the flow of fluid Purpose: This valve is used to speed up the piston movement and also it acts as a one way restriction valve which means that the air can pass through only one way and it can‟t return back. By using this valve the time consumption is reduced because of the faster movement of the piston. g. L-angle: Mild steel „L‟ type angle is used to fabricate the frame to mount the all the parts of the injection molding unit. h. Nozzle: The nozzle is used to inject the molded plastic material into the die. i. Die: The die is used to produce the required product. By using different Types of die different products can be formed. 4 Hose connector: In our pneumatic system there are two types of connectors used. Reducers are used to provide inter connection between two pipes or hoses of different sizes. tee. “V” or other configurations. These types of connectors are made up of brass or Al or hardened steel. one is the hose connector and the other is the reducer. These hoses can with stand at a maximum pressure level of 10 kg/cm2. These reducers are made up of gunmetal or other materials like hardened steel etc. They may be fitted straight.1 Double Acting Pneumatic Cylinder Stroke length Piston rod Quantity Seals End cones Piston Media Temperature Pressure Range : : : : : : : : : Cylinder stoker length 160 mm = 0.j.2.2 Technical Data 2.16 m 18 mm = 18 × 10¯³ m 2 Nitride (Buna-N) Elastomer Cast iron EN – 8 Air 0-80 º C 8 × 105 N/m² 5 . Hose connectors normally comprise an adapter (connector) hose nipple and cap nut. 2. Hoses used in this pneumatic system are made up of polyurethane. 635 × 10 .5 mm = 3.2.4 Hoses Max pressure Outer diameter Inner diameter : : : 10 ×10 ⁵ N/m² 6 mm = 6 × 10 ¯ ³m 3.2.5 × 10 ¯ ³m 6 .² m 0-8 × 10 ⁵ N/m² Air 1 10 × 10 ⁵ N/m² 0-100 ºc Air Brass Max working pressure: Temperature Fluid media Material : : : 2.2.2 Solenoid Valve Size Part size Max pressure range Quantity : : : : 0.2.3 Flow Control Valve Port size Pressure Media Quantity : : : : 0.635 × 10 ¯² m 0.635 × 10 ¯² m 10 × 10 ⁵ N/m² 2 2. 635 × 10 -² m 40 mm = 40 × 10¯ ³m b. Pneumatic unit Type of cylinder Type of valve Max air pressure : : : Double acting cylinder Flow control valve & solenoid valve 8 × 10⁵ N/m² d.1m c. Drill unit Short capacity Barrel diameter (ID) : : 0.8 m 441. Clamping unit Clamping Max Clamping Size : : Auto clamping 100 mm = 0.3General Machine Specifications a.4 m x 0.45 N 7 .2. General unit Size of machine (L x H) Weight : : 0. 2.4 Design Calculation Pressure applied Max pressure applied in the cylinder (p) Diameter of piston rod (D) Area of cylinder (A) : : : = = : 8 × 105N/m² 4 × 10-2 m 12.14 D²) / 4 Force exerted in the piston (F) : Pressure applied x Area of cylinder.56 × 10-4m2 = 10. = 8 N/m2 ×12.56 × 10⎯⁴ m² (3.48 × 102N 8 . 5 DESIGN DRAWINGS FIG 1 L-BEAM 9 .2. FIG 2 10 . BARREL FIG 3 11 . SUPPROT FOR BARREL FIG 4 12 . SUPPORT FOR VICE FIG 5 13 . ROTATING HANDLE FOR FIXTURE FIG 6 14 . PNUEMATIC CYLENDER FIG 7 15 . ASSAMBLY VIEW FIG 8 16 . LAYOUT DIAGRAM 17 . Stress = Internal resistance / Area of cross section. Elasticity: The property of a material body to regain its original condition on the removal of the deformation forces is called elasticity. Strain = Change in length / Original length c. b. Factor of Safety a. This internal resistance per unit area is called intensity of stress or simple stress. a. Strain has no unit since it is only a ratio. Working Stress b.CHAPTER-3 FACTORS INFLUENCING THE DESIGN The following are the factors influencing the fabrication work. 18 . Hooke‟s Law e. Working strain c. Bulk Modulus f. Working Strain: The deformation per unit length is called strain. Elasticity d. Poisson Ratio g. Working Stress: The internal resistance must be equal to the external load if the body is to be in equilibrium. Bulk modulus: The ratio of the change in the volume to the original volume of the body is known as the volume strain or the bulk strain. Factor of safety = Ultimate stress / Working stress. g. The ratio is called the Poisson‟s ratio and is denoted by 1/m Poisson‟s ratio 1/m = Lateral strain / Linear strain. The value of 1/m lies between 0.25 to 0. f. e. Stress / Strain is a constant. Hooke’s law: It states that when a material is loaded with in its elastic limit the stress is proportion to the strain. Poisson’s ratio: With in the elastic limit the lateral strain bears a constant ratio with the linear strain. 19 . Factor of Safety: The ratio of ultimate stress to working stress is known as factor of safety. The ratio of the bulk stress to the bulk strain of a body is called the bulk modulus.d . CHAPTER-4 INTRODUCTION TO POLYMERS The term polymer denotes a molecule made up of the repetition of simple unit monomers. For one thing. it becomes increasingly softer sand. polymer.1. high temperature & high press. turns into a very viscous. Plastics are produced from the polymers by the combination of latter with compounding of the plastics. 20 . viscous molten polymer does convert it into various gases but they are no longer polyethylene. This polymerization reaction consists of the use of a catalyst.1 Important Polymers 4. A polymer is produced from the monomers characterized by reactive centers. Depending on these conditions one gets a In the modern age.1 Polyethylene: This polymer is obtained from ethylene. as a result of polymerization reaction. which is a by product in petroleum industries. A polymer like polyethylene does not melt sharply at one particular temperature into a clean liquid. Instead. they are complex and giant molecules and are different from low molecular weight compounds like common salt. There are two types they are. Further heating of this hot. when converted into plastics. 4. the human beings make use of one or stowed other material made up of plastics in their daily routine. ultimately. The imperial chemical industries produced polyethylene by polymerization of ethylene. tacky molten mass. The importance of the polymers relates to it existence as a material. Low density polyethylene. 4. The emulsion 4. 21 .1.2 Polypropylene: The polymer is obtained from polymerization of propylene using co-ordination catalyst with the press up to 5 atmospheres & at temperature range (40-110) yield polypropylene.3 PolymethylMethacrylate: Polymethylmethacrylate is produced by radial polymerization of methyl methacrylate which is produced from acetone.1.1. 4. High density polyethylene. The monomer is subjected to emulsion method of polymerization using peroxide using the indicator. 4.a.1. b.4 Polyvinyl Chloride: The monomer is prepared from the reaction of acetylene with HC 1. Polymerization is carried out in suspension or emulsion method. polymerization is carried out at low temperature.5 Polyhedral Fluor ethylene: The monomer Tetrafluoro ethylene is prepared from the dechlorination of system dichloride tetra fluroethane. Polyesters. Thermosetting plastics are permanently hardened when formed.(Saturated). Thermoplastics are produced generally by addition polymerization while thermosetting plastics are produced by condensation polymerization. Polyamides. The following materials are thermoplastics: Polyethylene. heating affects the chemical structure and the plastics crumble to powder. Thermoplastics b. Polypropylene. Thermosetting plastics. in thermosetting plastics. Thus the processing of these materials has to be done in different manners. Thermoplastics are materials that can be softened by heat and then formed.1 Thermoplastics and Thermosetting Plastics Plastics are formed by the combination of polymers with compounding ingredients. 22 . Nylon.CHAPTER-5 CLASSIFICATION OF POLYMERS 5. Ply Acrylics. These are classified as a. Polyvinyl Chloride. Polystyrene Celluloses. During heating followed by cooling of thermoplastics. the bonds soften but the destruction of materials do not take place on the other hand. 23 These decorative .2 Plasticizers: They are added to the polymers to increase plastic property and induce more flexibility to the plastics. it is essential to have polymers blended with some external materials. Mel Amine-Formaldehyde Resins. 5. The components of compound of plastics: • • • • • • Fillers Plasticizers Colorants Lubricants Sterilizer Anti Oxidants. 5.2.2. To produce plastics. Urea Formaldehyde Resins. These external materials are termed “compounding ingredients”.2.3 Colorants: They are added to provide pleasing colors to the plastics. colors are provided by both organic dye stuff and inorganic salts. Polyesters (Unsaturated) Epoxy Resins Silicon.2 Components of plastics The following materials are thermosetting plastics: Phenol-Formaldehyde Resins. 5.1 Fillers: They are added to the polymers to impart special properties and also to reduce the cost of finished products. For the purpose of processing of polymers two plastics these are added to give not only the required property to plastics but also sturdiness and economical aspects to virgin polymers.5. called stabilizers.5. which result in declaration of the polymer.2.2.6 Antioxidants: Polymers are protected against oxidative degradation by incorporating certain compounds called antioxidants.2.4Lubricants: These substances are used to get a good finishing. 5.5 Stabilizers: The polymers may undergo degradation with the formation of conjugated double bonds along the chain. 5. 24 . To avoid this suitable materials are added. These are added to most of the polymers to improve flow within processing machineries and to reduce friction. the need to understand finer aspects of polymer processing surfaced as conventional materials were required to be substituted by those with better finish and elegant. polymers would often have some crucial role to play. 25 . In a very broad sense. polymer processing may be defined as an engineering specialty used to convert polymeric materials into useful end products. They black ebony or the costly ivory keys in a harmonium or a piano gave way to wooden keys with a covering of celluloid.CHAPTER-6 POLYMER PROCESSING Whether we want to make a toy or fabricate a spacecraft. But how does one convert a polymer into a broad spectrum of useful shapes and structures? To answer this question. Most of the available techniques now employed in processing technology of polymers are basically refined versions of those used in ceramic or metal industries. we need to look at another branch of polymer technology called “polymer processing” which it‟s the theme of this chapter. In fact. extrusion moulding. blow moulding. sheets. Fibers are made by a process known as spinning. reinforcing. coatings or adhesives and also as moulded and fabricated articles implies that there must be a variety of ways in which the compound resins can be processed and converted in then finished products. casting. Today. foams. the important ones being calendaring. tubes. dry spinning and wet spinning. while many others are made by casting liquid pre polymers into a mould and allowing them to cure of cross-link. foaming. compression moulding. injection moulding. melt spinning. there are many processes and automatic machines for this purpose. thermoforming. A majority of the articles are either moulded or fabricated.CHAPTER-7 PROCESSING TECHNIQUES The very fact that polymeric materials are used in many forms such as rods. 26 . cold forming. The locking device has to be very skillfully designed in order to withstand high operating pressures. Here.1 injection moulding The injection moulding process is best suited for producing articles made of thermoplastic materials. is a two-part system. In injection molding. Usually. The injection moulding machine is shown in the process consists of feeding the compounded plastic material as granules. this temperature is slightly lower than the softening temperature of the plastic material undergoing moulding. pellets or powder through the hopper at definite time intervals into the hot horizontal cylinder where it gets softened. a proper flow of the molten material to the interior regions of the mold is achieved by preheating the mould to an appropriate temperature.CHAPTER-8 INJECTION MOULDING PROCESS 8. One is a movable part and the other stationary. The stationary part is fixed to the end of the cylinder while the movable part can be opened or locked on to the stationary part. 27 . a definite quantity of molten thermoplastic material is injected under pressure into a relatively cold mold where it solidifies to the shape of the mould. The molten plastic material from the cylinder is then injected through a nozzle material from the cylinder is then injected through a nozzle into the mould cavity. The mould used. Pressure is applied through a hydraulically driven piston to push the molten material through a cylinder into a mould fitted at the end of the cylinder. the equipment cost is relatively high but the main attraction is the amenability of the injection moulding process to a high production rate. in its simplest form. Furthermore. After the mould‟s filled with the molten material under pressure. 28 . then it is either cooled by cold water circulation or air and then opened so as to eject the molded article. The whole cycle could be repeated several time either manually of in an automated mode. The pneumatic injection moulding machine is shown in the process consists of feeding the compounded plastic material as granules. a proper flow of the molten material to the interior regions of the mold is achieved by preheating the mould to an appropriate temperature. is a two-part system. Usually. By using a mechanical locking device. In pneumatic injection molding. Here. Furthermore. The stationary part is fixed to the end of the cylinder while the movable part can be opened or locked on to the stationary part. The mould used. One is a movable part and the other stationary. in its simplest form. the mould is proper held in position as the molten plastic material is injected under a pressure as high as 15×10-2 N/m2. a definite quantity of molten thermoplastic material is injected under pressure into a relatively cold mold where it solidifies to the shape of the mould. pellets or powder through the hopper at definite time intervals into the hot molten plastics. The locking device has to be very skillfully designed in order to withstand high operating pressures. Pressure is applied through a pneumatically driven piston to push the molten material through a barrel into a mould fitted at the bellow the nozzle.CHAPTER-9 WORKING PRINCIPLE The Pneumatic injection moulding process is best suited for producing articles made of thermoplastic materials. 29 . The molten plastic material from the Hooper is then injected through a nozzle material. the equipment cost is relatively high but the main attraction is the amenability of the pneumatic injection moulding process to a high production rate. These all valves are already explained in the above chapter. then it is cooled by cold water circulation and then opened so as to eject the molded article. After the mould is filled with the molten material under pressure. The whole cycle could be repeated several times by the same procedure. The double acting pneumatic cylinder is used to inject the molten plastic material into the die.this temperature is slightly lower than the softening temperature of the plastic material undergoing moulding. The direction control valve is used to control the direction of piston movement. 30 . The flow control valve is used to control the flow of air in to the cylinder. The two shafts hold two plates by drilling & boring the plate according to the required size. 10. The frame is finished accurately & it has provisions to mount the components.CHAPTER-10 FABRICATION OF MECHINE The injection moulding is widely used in the modern age. The upper plate holds the Rack & pinion gear mechanism. spring. The frame is designed like a chassis frame with the help of L angle. 31 .1 Rack And Pinion Gear: The rocker & pinion is the main part of the Injection system in injection molding. On one side square thread is made & thread is made on another side. Barrel. Heating Coil. There is also two shafts to hold two plates rigidly. The human beings make use of one or other material made up of plastics in their routine life. The plastic cannot be injected without Rack & Pinion. plunger. The shafts are tightened by using of hardware. nozzle. The Rack & Pinion makes the operation of Injecting system. There is also a provision to mount the channels on which the die locking & Die setting system works The threads are formed on the shafts. The two shafts are mounted on the either side of the channel. Rotating wheel. The bottom plate holds Hooper. The plates are fixed up and down on the shafts. Heating Coil Regulator is used to regulate the temperature of Heating coil. d.10. e. by poor rolling. a. Pitch Circle Diameter The pitch circle die is the diameter of an imaginary dix which would produce the same motion as that produced by the gear. Dedendum Circle: A circle passing through the roots of the teeth is called dedendum circle. Addendum: The part of the tooth out side the pitch circle is called the addendum. b. 32 .1 Gears: Classification of a. Addendum Circle: A circle passing through the tips of the teeth is called addendum circle.2 Construction of Gears: The following are the term used in gears.1. Pitch Circle: The pitch cycles are the outlines of the imaginary smooth rollers or discs. Spur gear b. worm and worm wheel d.1. c. helical gear 10. bevel gear c. The plunger moves up & down. Dedendum: The distance between center to center of two teeth measured along the arc of the pitch circle is called his circular pitch. 10.f. b. 10. Module: Module is the length of the pitch circle dia per tooth & is given by. The plunger is used to compress the molten plastic.2 Types Of Springs: Two types of springs are in common use. Rotating wheel: The rotating wheel is arranged with the pinion. a. 33 . Rock & pinion gear arrangement is used to convert the linear motion into rotary one & vice versa. Helical spring.1. Plunger: The plungers are attached with the rack. The Bearings are attached on either side of the pinion to give the support to the wheel rod. By rotating of the wheel. g.3 Working: A gear whose pitch circle dia is infinity is called as rack. By making external threads on rack and internal threads on plunger. Leaf spring. The small gear which meshes with rock is called the pinion. when the head stock spindle rotates the lead screw rotates at same speed the pitch of the work will be equal to the pitch of the lead screw. Helical spring of two types. The longitudinal feed should be equal to the pitch of the thread to be cut per revolution of the work. Closely Coiled Helical Spring: In a closely coiled helical spring the gap between successive turns is so small that each turn is practically a plan at right angles to the axis of the helix and the wire is subject to torsion. So far obtaining different pitches on the work. Helical spring: A Helical spring is formed by bending a wire around a mandrel in the form of a helix. The lead screw has a fixed pitch.3 Thread: When the job is rotated the tool is automatically moved by the lead screw in the longitudinal direction. The lead screw is connected by carriage by engaging the half nut lever. The bending stress is negligible compared to the tensional stress.a. a ratio between the rotation of the head stock spindle and the longitudinal feed is found out. So. • • Closely coiled helical spring. 10. As a result of this the spring can take up compression load also. Open Coiled Helical Spring: In a open coiled helical spring there is a large gap between the two consecutive turns. The coil in a helical spring is subjected to torsion and hence its known as Torsion spring. 34 . the speed of the lead screw can be changed by fixing proper change gears between head stock spindle and leadscrew. Open coiled helical spring. So. This spring can take up tensile load only. I Mild steel C.Component 35 .I Copper C.I Polyurethane Aluminium Aluminium C. 1 2 3 4 5 6 7 8 9 10 11 12 Name of The Parts Pneumatic cylinder Direction control Valve Flow Control Valve Barrel L-stand Vice Heating coil Hooper Connector Hose collar Reducer Nozzle EN-8 Material 1 1 1 1 1 1 1 1 Aluminum Aluminum C. No.CHAPTER-11 BILL OF MATERIALS Sl.I Quantity 5 meter 4 2 1 Table 1. 1 2 3 4 5 6 7 8 9 10 Name Of The Parts Pneumatic cylinder Direction control Valve Flow Control Valve Barrel L-stand Vice Heating coil Hopper Connector Nozzle Table 2. 7600 12.2 Total Cost Total cost = = Material Cost Charges Rs 7600 Total Cost of Machine = RS 7600 36 .1Material Cost: Sl.CHAPTER-12 COST ESTIMATION 12. Cost of Components Quantity 1 1 1 1 1 1 1 1 5 meter 1 Amount In Rs 2000 550 600 2000 200 300 1500 300 100 50 Total =Rs. No. No fire hazard problem due to over loading. Easy to maintain and repair. Occupies less floor space.CHAPTER-13 ADVANTAGES AND APPLICATIONS 13. It reduces the manual work. 37 . Cheaper and easily available material is used. Continuous operation is possible without stopping. Less skilled operator is sufficient.1 Advantages • • • • • • • • • • • • • • • • This product is an alternative for plastic cups and plates. Quick response is achieved Simple in construction. It reduces the production time. Adjustable Temperature setting is done with the help of thermo stator. Cost of the unit is less when compared other moulding machine. Different shape of the components can be made according to the die what are used. Comparatively the operation cost is less. The pneumatic arm is more efficient in the technical field. 3 Disadvantages • • • Initial cost is high Cylinder stroke length is constant Need a separate compressor 38 . we can produce any shape of plastic materials with low cost. By changing proper die. 13.2Applications • • • • The daily using plastic components can be easily made.13. It is very useful in small scale moulding industry Textile products can be produced. this working model can be successfully inducted in small scale moulding units and can be used to manufacture small plastic component at an acceptable cycle rate within an effective cost component. Existing market machine cost Component cost Total cost 45000. Cost estimation of fabricated machine 39 .00 Table 4. Cost evaluation of existing machine Fabricated machine cost 7600.CHAPTER-14 CONCLUSION Due to it‟s low cost.00 Table 3.00 Component cost Total cost 7600.00 67500.00 7600.00 22500. As exhibited in the above tables. This prototype can be subjected to further improvement in product cycle time with the compromise of the cost based component. After the completion of fabrication the machine is tested with a wide variety of acrylic plastic materials over a variable temperature range and plastic ring as the standard product from the die is manufactured. 40 . • Manual temperature control system can be replaced with a sensor based temperature range control system in order to make the process continuous and improve the cycle time. the newly fabricated machine has brought in a considerable reduction in the cost component when compared to existing cheapest machine available in the market Thus we have successfully fabricated a machine which can remove the initial starting cost hurdle and on basic standards cater to the needs of a small scale industry. A few of the changes which can be brought about are: • Introduction of a pneumatic based clamping system instead of the manual clamping system in order to decrease the cycle time and increase the overall production rate. ISSN: 1533905X. 6. Compressed Air Operations Manual.ISBN 0887307329. Tim A. Donald V. Machine Design 8. 9. Douglas M. 2000 Concise Encyclopedia of Plastics. Plastic Injection Molding: Manufacturing Process Fundamentals. R. Minimization of sink mark defects in injection molding process –Taguchi approach 4. 2.REFERENCES 1. ISBN 0-07- 147526-5. Rosado. Marlene G. Springer. Stephen Fenichell.Gramamn2007. Rajput. Injection Molding Handbook 2nd Ed. Paul J. Lih-Sheng Turng. R. Oswald.K.. International Journal of Engineering. 5. Science and Technology.S. Heat and Mass Transfer 7. Rosado. 3. SME. Journal of Injection Molding Technology.Plastic: The Making of a Synthetic Century. 1996. . McGraw Hill Book Company. Harper Business. 1996.HanserVerlag.Khurmi. Society for Plastic Engineers. Bryce.
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